Dispersions of carbon nanotubes in copolymer solutions and functional composite materials and coatings therefrom

Abstract

A dispersion includes a plurality of non-chemically modified carbon nanotubes, a soluble block copolymer providing at least one block of a conjugated polymer and at least one block of a non-conjugated polymer, and at least one solvent. At 25° C. exclusive of any mechanical force and after one hour, at least 90% of the plurality of carbon nanotubes exist in the dispersion as isolated carbon nanotubes. The components of the dispersion can be combined with a polymer miscible with the block copolymer to form a carbon nanotube polymer composite upon removal of the solvent. The dispersion can be cast on a substrate and then dried to form a coating, including forming a superhydrophobic coating on the substrate. The non-conjugated polymer of the block copolymer or another miscible conjugated polymer including a copolymer can include functionalities that non-covalently attach to the carbon nanotube surface, such as for manipulating carbon nanotube properties including for enhanced solubility or enhanced biocompatibility.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]This application claims the benefit of Provisional Application Ser. No. 60 / 978,881 entitled “Dispersions of Carbon Nanotubes in Block Copolymer And Superhydrophobic Materials Therefrom”, filed Oct. 10, 2007, which is herein incorporated by reference in its entirety.FEDERAL RIGHTS[0002]The U.S. Government has certain rights to embodiments of the present invention based on National Science Foundation CAREER awards (DMR 0746449, DMR 0552295 and ECCS 0748091), and NIRT award (DMI 0506531).FIELD OF THE INVENTION[0003]The invention pertains to methods for dispersing carbon nanotubes in block copolymers and dispersions, electrically conductive composites and functional materials therefrom, and devices comprising surface coatings that comprise electrically conductive carbon nanotube / block copolymer comprising composites.BACKGROUND[0004]Despite many of good electrical, mechanical and optical properties of carbon nanotubes (CNTs), applications for C...

AI Technical Summary

Benefits of technology

[0010]As used herein, the phrase “non-chemically modified CNTs” refers to CNTs that have an outer surface that is essentially exclusive of carbon atoms bonded to other species that result from breaking the carbon-carbon SP2 (π-π) bonds on the CNT surface. Thus, in embodiments of the invention, modification of surface of the non-chemically modified CNTs is achieved by delivering existing functional groups to CNT surfaces via the non-conjugated block in the block copolymer. In contrast, in conventional approaches, strong oxidants such as peroxides or strong acids such as nitric acid are used to break the carbon-carbon bonds on the CNT surface and turn them into polar groups, such as COOH groups.

[0011]In another embodiment of the invention, the non-conjugated polymer can

Problems solved by technology

Despite many of good electrical, mechanical and optical properties of carbon nanotubes (CNTs), applications for CNT's are still generally limited.

One of the main challenges faced for the development of CNT-based materials is the dispersion and stabilization of CNTs in a solvent media.

Exfoliation, using mechanical forces such as sonication, although simple and cost effective, generally results in poor quality dispersions.

Although chemical modification is generally effective as a dispersion method, such treatment inherently disrupts the long range nt conjugation of the nanotube, resulting in diminished electrical conductivity, mechanical strength, and / or a degradation in other properties.

However, such π-π interactions limit the solubility of the conjugated polymers in solvents and such CNT-conjugated polymers are generally immiscible with other polymer systems.

However, it is known that both MWCNT and SWCNT are cellular toxic.

Additionally, the P3HT / CNTs dispersions were not as stable as P3HT-b-PS dispersed CNTs as CNTs precipitation occurred in a few days.

Images